我在父子关系中使用javax.persistence.OneToMany关系。父ID为null，我已经阅读了Stackoverflow中的所有相关文章，但没有得到我所缺少的任何线索。
根据提供的序列，所有对应的PK都填充在父表和子表中，但是FK在子表中设置为null

家长班：

@Entity
@Table(name = "DIVERSITY_TEMPLATE")
public class DiversityTemplate implements Serializable {
    private static final long serialVersionUID = 1L;

    @Id
    @SequenceGenerator(name = "DIVERSITY_TEMPLATE_ID", sequenceName = "DIVERSITY_TEMPLATE_ID", allocationSize = 1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "DIVERSITY_TEMPLATE_ID")
    @Column(name = "DIVERSITY_TEMPLATE_ID")
    private Integer diversityTemplateId;

    @OneToMany(cascade = CascadeType.ALL, mappedBy = "diversityTemplate", fetch = FetchType.LAZY)
    private List<DiversityTemplateAttribute> attributes = new ArrayList<>();

儿童班：

@Entity
@Table(name = "DIVERSITY_TEMPLATE_ATTRIBUTE")
@TypeName("DiversityTemplateAttribute")
public class DiversityTemplateAttribute implements Serializable {
    private static final long serialVersionUID = 1L;

    @Id
    @SequenceGenerator(name = "DIVERSITY_TEMPLATE_ATTR_ID", sequenceName = "DIVERSITY_TEMPLATE_ATTR_ID", allocationSize = 1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "DIVERSITY_TEMPLATE_ATTR_ID")
    @Column(name = "DIVERSITY_TEMPLATE_ATTR_ID")
    private Integer diversityTemplateAttributeId;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "DIVERSITY_TEMPLATE_ID", nullable=false, referencedColumnName = "DIVERSITY_TEMPLATE_ID")
    private DiversityTemplate diversityTemplate;

服务等级：

 diversityTemplateRepository.save(diversityTemplate);

样本json

{
  "diversityTemplateId": 0,
  "attributes": [{
    "diversityTemplateId": 0,
    "diversityTemplateAttributeId": 0,
  }, {
    "diversityTemplateId": 0,
    "diversityTemplateAttributeId": 0,
  }]
}

请提出建议。